The sensitivity of so-called non-activated polymerization of ε-caprolactam to the presence of water in the polymerization mixture has been studied. Polymerizations were initiated with 1
mol% sodium ...salt of ε-caprolactam, magnesium di(ε-caprolactamate) and/or ε-caprolactam magnesium bromide and were carried out at water concentration 0–1
mol% and in the temperature range of 190–230
°C. The influence of water content in the polymerization mixture on the polymerization rate and polymerization degree was evaluated. The studied initiators exhibited different sensitivity to the water added in the polymerization mixture and the role of water in the course of anionic polymerization of ε-caprolactam is discussed. Magnesium initiators are exceptional, they are capable to eliminate retardation effect of water on studied polymerization.
Pipe hydrophone is an acoustic sensor that is widely used to measure sediment discharge in mountainous rivers in Japan. Monitoring data has been dramatically increased in the last decade. However, ...because the sound pressure of small colliding grain is smaller than that of the noise due to water flow, there is a lower limit of detectable grain diameter. Also because some of sediment grains do not collide against the pipe, the sediment discharge may be underestimated. Here we carried out the flume experiments on the same installation condition with general field measurements and measured the sound pressure of the noise due to water flow and that of the colliding grain. Then we analyzed a lower limit of detectable grain diameter and estimated the collision ratio by the same method Uchida et al. (2015) proposed. The results of this study are as follows. (1) On the experimental flume because the magnitude of the noise due to water flow was dependent on the noise near the water surface, the noise due to water flow became larger with the water depth became more shallow and the turbulence of the water surface became larger. (2) Based on the result, we estimated that on individual collision in case the diameter was 2 mm detecting probability was around 40% and in case the diameter was 3 mm detecting probability was more than 90%. On collective collision in case the diameter was 1 mm detecting probability was around 30% and in case the diameter was 2 mm detecting probability was almost 100% (3) In case dimensionless tractive force took a value within the range of 0.1≦τ ＊＜0.3 and the collision ratio ranged between 0.3 to 0.7.
A model, influence of water and salt on vegetation (IWSV), was developed to evaluate their influence on plant species. The main function of this model was to calculate a comprehensive index value for ...evaluating the suitability of plant growth. This model consists of five explanatory variables (vadose zone moisture content, vadose zone salinity, vadose zone lithology, depth to the water table, and groundwater mineralization) and two response variables (plant species and their cover). A set of independent data on three plant species,
Artemisia ordosica
,
Salix psammophila,
and
Carex enervis
, which are dominant species in the Mu Us Desert of northern China, were used to validate the model. Validation results show an overall correct prediction for the distribution of these three species. The results demonstrated that the IWSV model can be a useful tool for groundwater management and nature conservation in a semi-arid desert region, especially for predicting the vegetation distribution in areas with groundwater extraction.
The catalytic activity of Au–TiO
2–In
2O
3 catalyst in the oxidation of CO in the presence and absence of added water vapour and using different pretreatment conditions was tested and compared with ...that of a Au–TiO
2 sample prepared using a commercial support used as a reference catalyst. The Au–TiO
2–In
2O
3 samples showed less activity than the standard Au–TiO
2 sample but could be reused after reaction up to 500 °C without loss of activity. The activity of Au–TiO
2–In
2O
3 catalysts for CO oxidation was relatively insensitive to the pretreatment procedures but showed quite distinct light-off curves compared with those of Au–TiO
2. Differences between the catalytic behaviour of the two Au-supported catalysts indicate differences in the relative ease by which the oxides become dehydroxylated by thermal treatments. Results for Au–TiO
2–In
2O
3 are consistent with a scheme in which at low temperatures (⩽264 °C), CO
2 formation involves gold sites with participation of hydroxyl groups of the support. Above this temperature, dehydroxylation of the support leaves the gold component with low activity, and the rate of CO
2 formation becomes equivalent to the rate obtained over the support alone. Cooling the samples back to room temperature recovers the initial activity of the gold, confirming that deactivation is completely reversible. Experiments conducted involving deliberate addition of water show that the deactivation caused by an excess of H
2O for both Au–TiO
2 and Au–TiO
2–In
2O
3 is also reversible, and that the extent to which water is retained is quite different for the two catalysts. Reaction mechanisms, taking into account the involvement of H
2O, are discussed.
The article describes the experimental research made in specific canal with free surface. It records the changes of velocity revolutions of the current meter propellers OTT in dependence on water ...temperature. The authors describe the methods of measuring, data evaluation and the ways their results can be used in practice in order to improve hydrometric propeller measuring.
This book stems from the American Chemical Society symposium, Large Scale Molecular Dynamics, Nanoscale, and Mesoscale Modeling and Simulation: Bridging the Gap, that delved into the latest ...methodologies and applications for largescale, multiscale, and mesoscale modeling and simulation. It presents real-world applications of simulated and synthesized materials, including organic-, inorganic-, bio-, and nanomaterials, and helps readers determine the best method for their simulation. It gets novices up to speed quickly and helps experienced practitioners discover novel approaches and alternatives.
The effect of water on the mechanical properties (tensile modulus, ultimate tensile strength, tensile strain, and specific work at break) of both chemically treated and untreated composites based on ...a recycled low-density polyethylene and linen yarn production waste is analyzed. It is found that three water sorption-desorption cycles change the tensile properties of both the materials irreversibly. This effect is considered as the result of partial fracture of the fiber-matrix interface.
The influence of water vapour on the photoemissivity of GaAs crystals has been measured. Water vapour belongs to the gases with strong poisoning effects; even small amounts of water below the ...detection limit of conventional RGA systems reduce the practical lifetime of a GaAs photocathode.
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